Table 1.
Weight and frequencies, in the training set (Lombardy region), of the 26 variables contributing to the Preterm Birth Score (PTBS), selected applying the LASSO method, via logistic regression.
| Variable | Frequency (%) | Weight | ||
|---|---|---|---|---|
| Term Birth | Preterm Birth | Total | ||
| n = 117,480 | n = 9358 | n = 126,839 | ||
| Drugs | ||||
| Pancreatic hormones | 63 (0.05) | 33 (0.35) | 96 (0.08) | 10 |
| Agents acting on the renin-angiotensin system | 803 (0.68) | 173 (1.85) | 976 (0.77) | 5 |
| Sex hormones and modulators of the genital system | 22,664 (19.29) | 3216 (34.36) | 25,880 (20.40) | 4 |
| Endocrine therapy | 567 (0.48) | 156 (1.67) | 723 (0.57) | 3 |
| Drugs used in diabetes | 459 (0.39) | 112 (1.20) | 571 (0.45) | 3 |
| Immunosuppressants | 266 (0.23) | 53 (0.57) | 319 (0.25) | 2 |
| Corticosteroids for systemic use | 13,200 (11.24) | 1341 (14.33) | 14,541 (11.46) | 1 |
| Beta blocking agents | 1034 (0.88) | 163 (1.74) | 1197 (0.94) | 1 |
| Calcium channel blockers | 498 (0.42) | 98 (1.05) | 596 (0.47) | 1 |
| Hospital diagnosis | ||||
| Heart failure | 3 (0.00) | 5 (0.05) | 8 (0.01) | 8 |
| Chronic renal failure | 2 (0.00) | 4 (0.04) | 6 (0.00) | 4 |
| Diffuse diseases of connective tissue | 31 (0.03) | 13 (0.14) | 44 (0.03) | 3 |
| Inpatient procedures | ||||
| Other operations on rectum and perirectal tissue | 7 (0.01) | 7 (0.07) | 14 (0.01) | 12 |
| Diagnostic procedures on liver | 23 (0.02) | 12 (0.13) | 35 (0.03) | 4 |
| Lysis of peritoneal adhesions | 586 (0.50) | 132 (1.41) | 718 (0.57) | 4 |
| Exemptions | ||||
| Transplant recipients | 13 (0.01) | 12 (0.13) | 25 (0.02) | 8 |
| Diabetes mellitus | 303 (0.26) | 83 (0.89) | 386 (0.30) | 4 |
| Systemic lupus erythematosus | 97 (0.08) | 27 (0.29) | 124 (0.10) | 4 |
| Affections of the circulatory system | 343 (0.29) | 56 (0.60) | 399 (0.31) | 1 |
| Chronic (active) hepatitis | 270 (0.23) | 51 (0.54) | 321 (0.25) | 1 |
| Outpatient services | ||||
| Psychiatry | 4324 (3.68) | 549 (5.87) | 4873 (3.84) | 1 |
| General consultation | 474 (0.40) | 86 (0.92) | 560 (0.44) | 1 |
| Socio-demographic conditions | ||||
| Age at conception ≥36 years | 22,095 (18.81) | 2723 (29.09) | 24,818 (19.57) | 3 |
| Born abroad | 14,014 (11.93) | 1300 (13.89) | 15,314 (12.07) | 1 |
| Low education | 20,597 (17.53) | 1815 (19.39) | 22,412 (17.67) | 1 |
| Use of assisted medical conception techniques | 6005 (5.11) | 1587 (16.96) | 7592 (5.99) | 10 |